Figure 4

The ARF-GDP exchange activity of the coimmunoprecipitates with the insulin receptor. The exchange activity was determined as described in Materials and Methods. (○,□) Receptors were immunoprecipitated in the absence of insulin from cells transfected with empty vector (○) or with myc-ARNO (□). (●,■) Receptors were immunoprecipitated in the presence of insulin from cells transfected with empty vector (●) or with myc-ARNO (■).